A practical approach for computing Breit-Pauli spin-orbit matrix of large molecules using our recently developed redox spin-flip method (SF-IP/EA) is presented. By using a reference which differs in both the total number of electrons and the total spin-projection, the method can effectively treat systems with both spin and spatial degeneracies simultaneously. The spin-orbit matrix elements of all the multiplet components are obtained from a single reduced one-particle density matrix using the Wigner-Eckart theorem. The two-electron contributions to the spin-orbit interactions are accounted by means of a mean field spin-orbit approach. Good accuracies are obtained by including additional hole and particle excitations which have a favorable low computational scaling. The approach is validated by comparison to experimental and previously published data. The application range of the approach is illustrated by calculating spin-orbit splitting in paramagnetic metal complexes through the state-interaction procedure.

Spin-orbit matrix elements for a combined spin-flip and IP/EA approach

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

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